TODAY’S STUDY: Don’t Blame New Energy – It Has High System Value
Impacts of Variable Renewable Energy on Bulk Power System Assets, Pricing, and Costs
Ryan Wiser, Andrew Mills, Joachim Seel, Todd Levin, Audun Botterud, November 2017 (Lawrence Berkeley National Laboratory and Argonne National Laboratory)
We synthesize available literature, data, and analysis on the degree to which growth in variable renewable energy (VRE) has impacted to date or might in the future impact bulk power system assets, pricing, and costs. We do not analyze impacts on specific power plants, instead focusing on national and regional system‐level trends. The issues addressed are highly context dependent—affected by the underlying generation mix of the system, the amount of wind and solar penetration, and the design and structure of the bulk power system in each region. Moreover, analyzing the impacts of VRE on the bulk power system is a complex area of research and there is much more to be done to increase understanding of how VRE impacts the dynamics of current and future electricity markets.
While more analysis is warranted, including additional location‐specific assessments, several high‐level findings emerge from this synthesis:
• VRE Is Already Impacting the Bulk Power Market: The temporal and geographic patterns in wholesale prices have changed in some areas with higher penetrations of VRE, e.g. in CAISO and ERCOT. Negative prices have also sometimes increased with VRE penetration, though the prevalence of negative pricing remains limited in most locations. For the nation as a whole, negative prices have concentrated in areas with significant VRE and/or nuclear generation along with limited transmission, with negative pricing also typically occurring during periods with lower system‐wide load. (see Chapter 3)
• VRE Impacts on Average Wholesale Prices Have Been Modest: Analysis of wholesale prices in several regions demonstrates that the impact of VRE on average annual wholesale prices has been limited so far. Since 2008, the dominant factor driving wholesale prices lower has been the declining price of natural gas, with VRE playing a comparatively modest role overall. (see Chapter 3)
• VRE Impacts on Power Plant Retirements Have So Far Been Limited: Given the relatively modest impact so far of VRE on average annual wholesale electricity prices, it is not surprising that we do not find evidence of a widespread impact of VRE on power plant retirements. While VRE impacts on electricity markets may be a contributor to retirement decisions for some specific units, to date there is little relationship between the location of recent (2010‐2016) coal, nuclear, and other thermal retirements and VRE penetration levels.
• VRE Impacts on the Bulk Power Market will Grow with Penetration: Though operators are reliably integrating VRE, modeling demonstrates that higher penetration of VRE will tend to: (1) prioritize flexible (both existing and new) and low‐capital cost generation units over less‐flexible and high‐ capital cost units; (2) require greater amounts of aggregate capacity (including VRE and non‐VRE capacity), flexibility, and reserves to manage reliability; (3) alter the temporal and geographic patterns of wholesale electricity prices, and (4) reduce wholesale electricity prices and potentially increase ancillary service prices, especially before capacity equilibration occurs over the longer term. (see Chapters 2 and 4)
• The ’System Value’ of VRE will Decline with Penetration: The system value of VRE—specifically, the ability of VRE to offset the cost of other bulk power system assets—will tend to decline on the margin as VRE penetrations increase. These declines result from changes in the energy and capacity values of VRE, and the changing need for balancing services and transmission capacity. Comparing resources based only on their levelized cost of energy (LCOE) does not adequately capture differences in contributions to system value or system costs. (see Chapter 5)
• Power System Flexibility Can Reduce the Rate of VRE Value Decline: Flexibility provided by generation, load, transmission, storage, operational procedures, and market design become more important with VRE. Such flexibility measures reduce the rate of decline in system value of VRE as penetrations increase, but sometimes come at a cost to the consumer that is not always accounted for in generation portfolio decision‐making. (see Chapters 2 and 5)
All generation types are unique in some respect—bringing benefits and challenges to the power system—and wholesale markets, industry investments, and operational procedures have evolved over time to manage the characteristics of a changing generation fleet. With increased VRE penetrations, power system planners, operators, regulators, and policymakers will continue to be challenged to develop methods to smoothly and cost‐effectively manage the reliable integration of these new and growing sources of electricity supply…